Miyake Yusaku, Sakoda Akiyoshi, Yamanashi Hiroaki, Kaneda Hirotaka, Suzuki Motoyuki
Eco-Techno Corporation, 1-2-8 Shinsuna, Koto-ku, Tokyo 136-0075, Japan.
Water Res. 2003 Apr;37(8):1852-8. doi: 10.1016/S0043-1354(02)00564-X.
Ground water contaminated with trichloroethylene (TCE) used in electronic, electric, dry cleaning and the like industries is often treated by air-stripping. In this treatment process, TCE in its vapor form is stripped from ground water by air stream and sometimes emitted into the atmosphere without any additional treatments. Activated carbon adsorption is one of the practical and useful processes for recovering the TCE vapor from the exhaust air stream. However, adsorption of the TCE vapor from the stripping air stream onto activated carbons is not so simple as that from dry air, since in the exhaust air stream the TCE vapor coexists with water vapor with relatively high concentrations. The understanding of the adsorption characteristics of the TCE vapor to be adsorbed on activated carbon in the water vapor-coexisting system is essential for successfully designing and operating the TCE recovery process. In this work, the adsorption equilibrium relations of the TCE vapor adsorption on activated carbons were elucidated as a function of various relative humidity. Activated carbon fibers (ACFs) were used as model activated carbon. The adsorption equilibrium relations were studied by the column adsorption method. The adsorption isotherms of TCE vapor adsorbed on sample ACFs were successfully correlated by the Dubinin-Radushkevich equation for both cases with and without coexistent water vapor. No effects of coexistent water vapor were found on the limiting adsorption volume. However, the adsorption characteristic energy was significantly reduced by the coexistence of water vapor and its reduction was successfully correlated with the equilibrium amount of water vapor adsorbed under the dynamic condition.
电子、电气、干洗等行业使用的受三氯乙烯（TCE）污染的地下水通常采用空气吹脱法进行处理。在该处理过程中，呈气态的TCE被气流从地下水中吹脱出来，有时未经任何额外处理就排放到大气中。活性炭吸附是从废气气流中回收TCE蒸汽的实用且有效的方法之一。然而，将TCE蒸汽从吹脱气流中吸附到活性炭上并不像从干燥空气中吸附那么简单，因为在废气气流中，TCE蒸汽与相对高浓度的水蒸气共存。了解在水蒸气共存体系中TCE蒸汽在活性炭上的吸附特性对于成功设计和运行TCE回收工艺至关重要。在这项工作中，研究了TCE蒸汽在活性炭上的吸附平衡关系与各种相对湿度的函数关系。使用活性炭纤维（ACF）作为模型活性炭。采用柱吸附法研究吸附平衡关系。对于有和没有水蒸气共存的两种情况，TCE蒸汽在样品ACF上的吸附等温线均成功地用杜比宁-拉杜舍维奇方程进行了关联。未发现水蒸气共存对极限吸附量有影响。然而，水蒸气的共存显著降低了吸附特征能量，并且其降低与动态条件下吸附的水蒸气平衡量成功关联。
